We propose to continue and/or complete the projects still in progress and to undertake new projects. Studies of prognostic factors in melanotic tumors of the iris and retinoblastoma have been proposed. In our continuation of cytologic evaluation of uveal nevi and melanomas, increased use of electron microscopy will be made in an effort to further refine the Callender classification and to assist in defining better the criteria for differentiating spindle cell nevi from spindle cell melanomas. Electron microscopy will also be employed to study the integrity of the vascular walls of dilated blood vessels that are so characteristically present, especially in the larger melanomas of epithelioid or mixed cell type that so frequently prove lethal after, but almost never before, enucleation. Comparisons will be made between the electron microscopic appearance of the vascular walls in eyes subjected to standard procedures of enucleation and those enucleated by the "no touch technique."